Nature Climate Change, Published online: 18 February 2021; doi:10.1038/s41558-021-00990-2
The 2009 pledge to mobilize US$100 billion a year by 2020 in climate finance to developing nations was not specific on what types of funding could count. Indeterminacy and questionable claims make it impossible to know if developed nations have delivered; as 2020 passes, opportunity exists to address these failures in a new pledge.
